Egg carton latch



United States Patent inventor Kurt G. Dahlberg Plttsford, New York Appl. No. 788,497 Filed Jan. 2, 1969 Patented Nov. 10, 1970 Assignee Thermo Trim lnc.

Rochester, New York a corporation of New York EGG CARTON LATCH 3 Claims, 9 Drawing Figs.

U.S. Cl 229/44, 229/45 Int. Cl 865d 5/66, B65d 5/10 Field of Search 229/44, 45, 2.5

References Cited UNITED STATES PATENTS Forrcr Alsman Despres... Boyd et a1. Morgese Commisso et a1..

Ward et al. Andrews et a1.

Primary Examiner-Raphacl H. Schwartz Attorney-Cumpston, Shaw and Stephens lllliil l 229/45X 229/45X 229/2.5 229/45X 229/45X 229/45X 229/45 229/44 ABSTRACT: An egg carton latch is formed with a latch surface on a latch flap that extends upward from the base of the I carton and an inwardly offset lower edge of an aperture in the latch region in the cover of the carton. Surfaces supporting the offset edge are tapered to converge with increasing distance from the offset edge.

Patented Nov. 10, 1970 3,539,092

Sheet 1 of 2 IN VIL'NTOR. KURT G. DAHL BERG BY an ,1

ATTORNEYS Patented Nov. 10, 1970 3,539,092

Sheet 2 of2 INVENTOR. KURT G. DAHLBERG BY d0,

ATTORNEYS EGG CARTON LATCH THE IMPROVEMENT EFFECTED Previously known, commercially successful egg carton latches have used projections extending outward from a latch flap on the cartons base with the projections extending through apertures in the cover to latch the cover down. The materials from which egg cartons are molded require that the projections be somewhat rounded, and this enables them to slip from a latch position occasionally. Also, such a latch arrangement depends heavily on the.outward thrust of the latch flap to force the projections through the apertures, and the latch is often unreliable, particularly after eggs have been removed from the spaces immediately behind the latch flap.

The objects of this invention include, without limitation, improving on such prior art egg carton latch by making a simple latch that is more positively engaged, and holds more reliably to a latched position in all circumstances. The inventive egg carton latch also meets many of the other requirements of modern egg cartons for simplicity, economy, nesting ability, a strong cover well braced over the base, and capacity for machine-loading and handling.

SUMMARY OF THE INVENTION The inventive egg carton latch includes a latch flap that extends outward from the base and is folded to tuck inside a latch region of the cover when the carton is closed; an aperture in the latch region of the cover portion formed with the edge nearest the closing edge of the cover offset inwardly from the plane of the latch region; support surfaces extending from the offset edge to the plane of the latch region and tapered to converge with increasing distance from the offset edge toward the closing edge of the cover; a latch surface on the latch flap facing toward the closing edge of the base portion with the flap shaped to afford free space below the latch surface for receiving the support surfaces below the offset edge as the offset edge snaps under the latch surface to latch the cover closed.

The latching by a raw edge engaging a latch surface which can also be a raw edge, affords greater friction and a more positive latch. Also, having the latch edge extend inward from the plane of the cover affords a more positive entry of the latch projection into engagement with the latch surface since the cover wall cannot bulge far outward and its inwardly projecting offset edges are brought forcefully into latch position as the cover closes.

THE DRAWINGS FIG. 2 is a front elevational view of a fragment of the egg carton of FIG. 1 in closed position to show the inventive latch;

FIG. 3 is a cross-sectional view of the latch of FIG. 2 taken along the line 3-3 thereof;

FIG. 4 is a plan view of a fragment of the latch of FIG. 2;

FIG. 5 is an elevational view from the inside of the cover of the egg carton showing the latch of FIG. 3;

FIG. 6 is a cross-sectional view of a fragment of an altemative preferred egg carton latch according to the invention; and

FIGS. 7 -9 are elevational views of fragments of the inventive carton showing finger access arrangements for opening the carton.

DETAILED DESCRIPTION The drawings show two preferred embodiments of the inventive egg carton latch to make the principles of the invention clear. However, other embodiments and variations on the inventive theme are possible within the spirit of the invention. The drawings schematically illustrate the base of the egg carton since its shape is not especially important to the inventive latch. Also, the cover of the inventive carton is illustrated in a ton, with the closing edge of cover 12 in registry with closing edge 14 of. base 11. A latch flap 15 extends outwar from base 11 and is joined to the closing edge 14 of base 11 along a fold line 16. Latch flap 15 is folded upward in use and tucked inside the latch region 17 of cover 12 as carton 10 is closed.

FIGS. 24 best show the inventive latch arrangement. An aperture 20 is formed in the latch region 17 of cover 12, and the lower edge 21 of aperture 20 is offset inward from the plane of latch region 17. Support surfaces 22 extend downward from offset edge 21 toward the closing edge 13 of cover 12 and outward to the plane of latch region 17 to support offset edge 21 in its inwardly extended position. Support surfaces 22 are tapered so they converge with increasing distance downward from offset edge 21. The top 23 of aperture 20 is preferably spaced above offset edge 21.

Support surfaces 22 turn outward toward the plane of latch region 17 at a distance below offset edge 21 to form rest surface 24 facing toward the closing edge 13 of cover 12. In the latched condition illustrated in FIG. 3, rest surface 24 is above the bottom edge 27 of aperture 25 so that downward pressure on cover 12 brings rest surface 24 into engagement with ledge 27 to brace cover 12 over base 11. This allows stacking of loaded cartons without bringing cover 12 down into engagement with the eggs.

FIG. 6 shows a preferred alternative of the inventive latch which differs from the correspondingly viewed latch of FIG. 3 in that latch flap 15 has a walled recess instead of an aperture for receiving offset edge 21 and support surfaces 22. Wall 30 surrounds a recess in latch flap 15 and includes a latch surface 31 engaged by offset edge 21, and a ledge surface 32 that supports rest surface 24 against downward pressure on cover 12.

Another difference in the latch of FIG. 6 is that upper edge 23a of aperture 20 in cover 12 is lower and closer to offset edge 21. Otherwise cover 12 is the same in FIG. 6 as in FIG. 3 including the taper of support surfaces 22. Preferably, recess wall 30 has the same taper to converge with distance downward from latch surface 31. Recess wall 30 provides a bearing surface to take advantage of any outward pressure on latch flap 15 by eggs loaded in base 11.

In operation, eggs are loaded in base 11, latch flap 15 is folded upward, and cover 12 is folded down over base 11 to close carton 10. Support surfaces 22 below offset edge 21 cam over the top of latch flap 15 as cover 12 is lowered. When offset edge 21 passes below latch surface 26 or 31, offset edge 21 is forced inward under such latch surface to latch cover 12 down. Any downward pressure on cover 12 brings rest surface 24 into engagement with ledge surface 27 or 32 to brace cover 12.

To open the carton, the upper edge of latch flap 15 is pressed inward by finger pressure in aperture 20 to release the latch so cover 12 can be raised. Alternatively, a notch or slit can be formed along the closing edge 13 of cover 12 to afford finger access to latch flap 15 for pressing latch flap 15 inward at some other point. Such arrangements are shown in FIGS. 7 and 8 respectively as an access notch 35 and an access slit 36. Also, a pair of slits 36 can be used as shown in FIG. 9 to provide a movable tab 37 that can be pressed inward to move latch flap 15 inward and allow opening of the carton.

Persons wishing to practice the invention should remember that other embodiments and variations can be adapted to particular circumstances. Even though one point of view is necessarily chosen in describing and claiming the invention, this should not inhibit broader or related applications within the spirit of the invention. For example, different numbers of cover apertures and offset edges can be associated with flap apertures or recesses, combinations of apertures and recesses can be used, and these elements can be given different positions, proportions and shapes.

lclaim:

1. An improved latch for a single-piece egg carton having a base portion for receiving eggs and a cover portion joined to said base portion for folding over said base portion to close said carton with the closing edges of said base portion and said cover portion close together in mutual registry, said latch comprising:

a. a latch flap extending normally outward from a fold line along said closing edge of said base portion;

b. in the closed condition of said carton, said latch flap being normally disposed inside and generally parallel with a latch region of said cover portion adjacent said closing edge of said cover portion;

c. said latch region of said cover portion having support surfaces offset inwardly from the plane of said latch region;

d. said support surfaces being tapered to diverge with increasing distance from said closing edge of said cover portion;

. said latch region of said cover portion having an aperture extending across said support surfaces and spaced from the end of said support surfaces closest to said closing edge of said cover portion;

. the edge of said aperture nearest said closing edge of said cover being inwardly offset and having a substantial length facing away fr'omsaid closing edge of said cover portion;

g. said latch flap having a walled recess offset inwardly relative to the plane of said latch flap;

h. said recess'being tapered to diverge with increasing edge of said base portion being configured-to forma latch.

surface extending generally perpendicular to the plane of said latch flap and facing toward said closing edge of said base portion; and

k. said latch surface being longer than said offset edge and positioned to latch over said offset edge in said closed condition of said carton.

2. The carton of claim 1 wherein the wall of said .walled recess closest to said closing edge of said base portion is con figured to define a ledge facing away from said closing edge of said base portion, and said support surfaces are configured to be closely parallel with said ledge in said closed condition of said carton to form a rest bracing said cover portion over said base portion.

3. The carton of claim 1 wherein said latch flap and said cover portion extend above said latch surface in said closed condition of said carton. 

